ASAP-Font Strikethrough issue in Firefox

I stumpled upon an issue with the ASAP-Font in Firefox, if the text should be striked through. No problem with other browsers. But in firefox the striking line is not centered over the text, it is placed under the text (like an underline). Cannot really explain the behaviour, so some screenshots:

### How it looks using Firefox:

### How it should look using chrome

**You can see it live here:**
https://www.spielmannszug-meschede.de/termine-2020/?customize_changeset_uuid=7f1c5329-04d3-4f31-878b-707142f51ec5

It's a specific firefox issue. It does not appear under Chrome. It seems to be not an css related issue, because i checked everything else first, till i came to the conclusion to switch the font. I don't know how a font is effecting its appearence for the text-decoration, but this has taken some time to find out.

### My system specifications:
OS: Microsoft Windows 10.0.18363
Firefox: 75.0 64Bit (with Add-On: uBlock Origin)